There are two types of LCD display constructions, i.e., cell and open cell during the manufacture process of a display module. In the cell structure, liquid crystal is filled in the gap between two substrates and then the two substrates are sealed to form a module, whose appearance is the same as a normal piece of glass. After the prior process is completed, connection ports are provided to a cell-based display module for external signal, i.e., open-cell. However, a backlight module is not included in the display module so made.
A display module cannot illuminate by itself but through the backlight module. As result, the backlight module is crucial in the display industry. The backlight module is composed of a light source, a light guide, an optical membrane, a rubber strip and a backboard. The illumination efficiency is dependent from the matrix arrangement between the backboard structure and the light source. Therefore, it is an issue to be solved in the design of backlight module to make it light-weight, thin, high luminosity and low cost.
In the existing backlight modules, most of the backlight modules are integrally formed. A backlight module, as shown in FIG. 1, has a liquid crystal plate 103, prism plates 104, 105, a diffusion plate 106, a reflection plate 107 and an LED board 108, all of which are sandwiched between a backboard 101 and a front frame 102. Side faces 1011 of the backboard 101 and side faces 1021 of the front frame 102 are sealingly combined such that the backboard 101 and the front frame 102 together form a sealed space. A rubber strip is provided to the side face 1011 of the backboard 101 and the side faces 1021 of the front frame 102 so that the liquid crystal plate 103, the prism plates 104, 105, the diffusion plate 106, the reflection plate 107 and the LED board 108 are firmly sandwiched between the front frame 102 and the backboard 101. Numerous light sources 1081 are mounted on top of the LED board 108, which allows light coming from the light sources 1081 to penetrate through the reflection plate 107, the diffusion plate 106, the prism plates 104, 105 as well as the liquid crystal plate 103 and eventually leave the front frame 102. As the front frame 102 and the backboard 101 are made of metal to gain the best heat dissipation effect, however, dismantling the combination of the backboard 101 and the front frame 102 for maintenance and repair is difficult and troublesome when there is malfunction happened to one or some of the light sources 1081.
Normally, there are some choices available for the metal for the backboard 101 and the front frame 102:
Aluminum: good for heat dissipation but bad for cost consideration;
Iron: iron is used for the backboard and an aluminum strip is provided to the side face for the light source for heat dissipation. This kind of design is bad for overall heat dissipation and increases the total weight of the backlight module, which is bad for the goal of lightweight.
In a Chinese patent CN202132887U, a design for backlight module is disclosed, numerous aluminum strips are provided to locations corresponding to places where the light sources are mounted and then iron is used for other portions, which ensures that the heat dissipation effect is good and the overall manufacture cost for the backlight module is low.
All the above statement uses an integral design for the backlight module. Nowadays, due to different requirements from the customers for different sizes of the displays, a large quantity of displays of different sizes are made to fulfill the requirements. However, in order to fulfill the requirements, manufacturers need to invest a lot of hardware such as production lines for different sizes of the displays, manpower and above all, a lot of money, which is not very good for budge control.